>1)How is the usual weather in Baja California in late August?
First of all Baja is a thousand-mile long peninsula with quite a variance in
temperature. August generally will be sunny and warm. More specifically;
Northern Baja from the border to El Rosario along the Pacific Coast will
have weather similar to San Diego's, beautiful warm days (in the 80ºs
Fahrenheit) and pleasant nights. Along the coast of the Sea of Cortez it
will be hot (in the 100 to 110ºF range).

Southern Baja, Cabo San Lucas will also be hot (probably in the 90ºF range).
There is also the possibility of tropical storms and even the remote
possibility of a hurricane. Although these are more likely in Sept. through
Nov.

>2)Is it very different from San Diego's climate?
In the north on the coast very similar. On the east coast and south much
hotter.

>3)Would you suggest choosing Baja for a week's rest after touring the west
coast,and if yes,what area is best?
Sure, Baja is a great place to unwind. It is best suited for camping. But
there are developments to stay at. Especially in the south around the Capes.

>4)How to get there, fast and cheap(well,reasonably adelante and not too
expensive)?
Well, depends on where you decide to go. If it's the Cape area you'll need
to fly. Otherwise it is a three day drive. In the north it would be possible
to rent a car and visit the area from the border (Tijuana) down to San
Quintin staying in hotels.

>We love dry and hot climate,but of course not sunbathing in an oven...
Baja's got you covered there. There's alot of possibilities. Here are some
websites to check out. If you have any more specific questions please ask.